This application is related to U.S. Pat. No. 5,303,102 entitled Disk Drive Apparatus Having Head Guard, to Tomoe Aruga et al and U.S. Pat. No. 5,303,104 entitled Disk Drive Apparatus Having Carriage Driving Mechanism to Tomoe Aruga et al. These applications and patents are incorporated herein by reference.
1. Field of the Invention
This invention relates to a disk drive apparatus for recording and reproducing information in and out of a floppy disk or the like, and more particularly, to a disk driving motor and chucking mechanism for a disk drive apparatus.
2. Description of Related Art
A disk driving motor assembly generally includes a disk chucking mechanism, and rotates a disk (held on a rotary member of the motor assembly by the chucking mechanism) together with the rotary member. Disk chucking mechanisms have been proposed in various forms. See, for example, Japanese Laid-Open Utility Model No. 61-52351.
FIGS. 11-14 show one such conventional disk driving motor assembly including a chucking mechanism. FIG. 11 is a vertical sectional view showing an example of a conventional disk driving motor assembly including a chucking mechanism. FIG. 12 is an overhead plan view showing the disk chucking mechanism. FIG. 13 is a bottom view of the disk chucking mechanism. FIG. 14 is a schematic sectional view showing a drive pin section of the disk chucking mechanism.
In these drawings, 501 is a disk, 502 is a disk hub, and 503 is a spindle of the disk driving motor. A chucking lever 508 is pivotally attached, via a support point 516, to a rotary member 504, which is rotatable together with the spindle 503. A spring 514 is provided at support point 506  516 to urge a drive pin 505 attached to the chucking lever 508 in the axial direction of the drive pin. Another spring 515 (see FIG. 12) is provided between rotary member 504 and chucking lever 508 to exert an urging force on lever 508 in the circumferential direction of the motor.
When the disk hub 502 is to be chucked (e.g., when it is initially set in place), the chucking lever 508 is pivoted at the support point 516 because one end of it is pushed downwardly by the disk hub 502 as shown in FIG. 14 with the result being that the chucking lever 508 deflects in the direction of the arrow r. Once spindle 503 (and thus rotary member 504 and chucking lever 506) are rotated, disk hub 502 continues to press the one end of lever 508 downward until a drive hole 502b formed in the disk hub 502 (in offset relation to the center thereof) comes into alignment with the drive pin 505 (see FIG. 11).
When a rotor 511 of a spindle motor 510, which is attached to one end of the spindle 503 (as shown in FIG. 11) begins rotating, the drive pin 505 also rotates together with the spindle 503. When the drive hole 502b comes into alignment with the drive pin 505, the drive pin 505 is urged into the drive hole 502b in disk hub 502 by virtue of the pushing force of spring 514.
Consequently, because of the positional relationship between the drive pin 505 and the support point 516, rotation of spindle 503 causes drive pin 505 to exert a force in the direction of the arrow s as shown in FIG. 12 to cause rotation of disk hub 502. Among these forces, the force in the direction of the arrow s acts to press two points along the inner edge of a central hole 502a of the disk hub 502 against the spindle 503, so that the disk hub 502 is rotated while also being centered.
As shown in FIG. 11, a first magnetic head 512 for recording and reproducing an information signal into and out of the disk 501 is disposed on a first carriage 517 between a frame 513 of the spindle motor 510 and the disk 501. A second magnetic head 507 is also provided to engage an opposite side of disk 501.
In the foregoing conventional configuration, however, it is difficult to decrease the thickness of the overall disk drive apparatus because its thickness is determined by the rotor 511 of the spindle motor 510, first carriage 517, first magnetic head 512, the space required for the disk chucking mechanism, etc.
One limitation in reducing the thickness of the disk drive apparatus is caused by the need to provide sufficient space below the drive pin 505 so that the drive pin 505 may retract in the direction of the arrow r as shown in FIG. 14 when the drive pin 505 is pushed by the disk hub 502 (before the disk hub 502 is chucked).
Further, to attach the rotary member of the rotor of the disk driving motor to the spindle, conventionally, as shown in FIG. 11, the rotary member 504 is tightly fitted to the spindle 503 using a bushing 518. Additionally, the rotor 511 is press-fitted to the spindle 503 by forming a cylindrical boss portion 511a integrally with the rotor. As another alternative, shown in FIG. 15, a rotor 521 is fitted to a bushing 522 which is in turn press-fitted to a spindle 523. In FIG. 15, 524 is a drive magnet, 525 is a drive coil, 526 is a motor base, 527 is a circuit board, and 528 is a bearing fitted to the motor base 526.
In the foregoing conventional configurations, however, in order to reduce the swinging (wobble) of the rotary member, or of the rotor relative to the spindle, the fitting section between the spindle and the boss portion 511a or the bushing 518 or 522 must have a certain axial length, this also making it difficult to decrease the thickness of the disk drive apparatus.
U.S. Pat. No. 4,697,216 to Tsukahara discloses a disk drive apparatus in which a yoke plate and a turntable form a two-piece rotary member. A ring plate, which forms a disk chucking mechanism and includes a drive pin, is located between opposed surfaces of the turntable and the yoke plate, and is pivotally attached to the yoke plate. A magnet plate 36 is provided over the yoke plate for attracting the metal hub of a disk. The opposed surfaces of the turntable and the yoke plate prevent the ring plate from moving in an axial direction of a motor shaft, which is attached to the yoke plate and causes the turntable and yoke plate to rotate. However, this structure is bulky because the turntable and the yoke plate both cover the entirety of both surfaces of the ring plate so as to clamp the ring plate between the turntable and the yoke plate, in order to prevent the ring plate from moving in the axial direction of the motor shaft.
It is an object of the present invention to simplify the configuration of a disk driving motor assembly which includes a disk chucking mechanism, and to decrease the thickness of the disk driving motor assembly as much as possible, thereby making a disk drive apparatus thinner.
To accomplish the foregoing and other objects, and to overcome the shortcomings set forth above, the present invention provides a disk drive apparatus that comprises a spindle for engagement with a central hole of a disk hub made of metal or the like which is provided in a central portion of a disk accommodated in a cartridge. A rotary member such as, for example, a rotor is fixed to the spindle. A chucking magnet is provided on the rotary member for magnetically attracting the disk hub. A chucking lever is pivotally provided on the rotary member, which has a drive pin near one end that comes into engagement with a drive hole (generally of substantially quadrangular shape formed in the disk hub in offset relation to the center thereof) to engage and rotate the disk. When the chucking lever is not chucking the disk, the chucking lever is pivotal about a support point within a given angle in the radial direction of the motor, spindle and disk, but its shifting in the axial direction of the spindle is restricted (prevented). A support point section of the chucking lever is provided with a disengagement preventive mechanism that acts in relaxation to the rotary member to prevent disengagement of the chucking lever from the rotary member.
As will be appreciated, since the chucking lever is pivotal about its support point within a given angle but its shifting in the axial direction of the spindle is prevented, the thickness of the disk drive apparatus can be decreased.
According to one aspect of the invention, the rotary member includes a slot, and the chucking lever permanently protrudes into the slot so that edges of the slot limit movement of the chucking lever in a direction perpendicular to an axial direction of the spindle.
According to another aspect of the invention, the chucking lever is provided on a surface of the rotary member that faces away from a disk, and the drive pin of the chucking lever extends through a hole in the rotary member, which limits movement of the chucking lever in the direction perpendicular to the spindle axial direction.
The disclosed structures prevent the chucking lever from moving in the axial direction of the spindle without requiring a separate clamp that extends over substantially the entire surface of the chucking lever. That is, the rotary member extends over substantially the entirety of only one side of the chucking lever, substantially the entirety of the opposite side of the chucking lever is not covered by any structure that prevents the chucking lever from moving in the spindle axial direction.
According to another aspect of the invention, the drive pin is made from plastic to reduce wear on the disk hubs of disks used with the disk drive apparatus.
Preferably, a rotor of a spindle motor for rotating the disk may be used as the foregoing rotary member.
In the case of the spindle motor, a circumferential groove may be formed in the spindle, a snap ring fitted in the circumferential groove, and the rotor press-fitted to the spindle and fixed onto the snap ring. The snap ring stably supports the rotor, preventing wobble, and securely holds the rotor so that it extends perpendicular to the axis-of the spindle, while reducing the length of contact between the rotor (and other rotor securement structure) and the spindle in the axial direction of the spindle.